This invention generally relates to method and apparatus for regulating the flow of water, more particularly, to water gates, and especially water gates in which the water gate turns about a pivot axis which is generally parallel to the horizon.
Major flooding too often happens in urban areas when runoff of surface water from sustained and heavy rains, or stream overflow, or cresting or penetration of water retention dikes, overwhelms water drainage and removal systems. At high risk in any such situation are buildings with subterranean areas including basements, subterranean tunnels and halls, parking garages and the like. Surface water invading through open entries of the buildings runs to lower levels. As lower levels fill, flooding can climb to higher subterranean floors and to adjacent buildings if buildings are connected by underground pedestrian or utility tunnels. If standby power generators and/or fuel powered water evacuation pumps are located below surface grade, such as in a basement, as all too often is the case, the power generators and water pumps can be disabled by water flooding into an area where they are located, removing often the last line of flood defense of the building.
Openings to buildings through which rising water can invade include entrances to covered receiving and loading docks, to underground parking areas and garages, to descending stairwells, and to vents, and potential entrances include grade-level and below grade windows or doors. Bottom-hinged xe2x80x9cflip-upxe2x80x9d flood gates, with inflatable gaskets, that are floor recessed when not in use, that have an exposed surface for traffic passage, and that are raised by hydraulic cylinders or winches, are commercially available. Other also not automatic building water barriers are shown in U.S. Pat. No. 5,943,832 for flood or storm resistant barriers for doorways or window opening; U.S. Pat. No. 5,283,979 for locking/opening system for watertight hatch, U.S. Pat. No. 4,582,451 for floodgate panel and sealing means therefor; and U.S. Pat. No. 4,355,000 for lightweight, removable gate seal.
Storms that produce locally heavy flooding occur only sporadically, so available flood gates of the art as described above remain in a retracted position for long periods of time. Because these flood gates are not automatic, on-site or on-call personnel are required to put them into barrier position when a high water inundation event is anticipated. When the event is a cresting river or the like, there is some advance notice. Unfortunately, nature sometimes comes calling torrentially, unexpectedly and inconveniently, when personnel are not on site, such as the middle of the night, and even if on-call, the personnel may be prevented by flooding of roadways from getting to the site in time to erect the flood gates before the structure meant to be protected is already inundated.
There have been efforts to automate erection of flood gates. One such example is U.S. Pat. No. 5,460,462, in which a vertically disposed flotation barrier elevates on guide tracks between channel posts when water rises within a vertical subterranean housing containing the flotation barrier. There are disadvantages, however, to such a vertical barrier. Hydrostatic forces generated by rising surface water press the barrier against its tracks, increasing friction and causing the barrier to resist the buoyancy forces working to raise the barrier vertically. Installation of the vertically disposed buoyant barrier requires evacuation of ground for the supporting structure to depth greater than the full height the barrier. Particularly in existing constructions such as parking garages and tunnels, the building structure itself or buried ancillary structure prevents excavations to a depth needed for placement of a vertical barrier. In addition, when a flood recedes, mud and flood debris from the water remain, and removal of debris from a tall, thin vertical slot in the ground, occluded with the flotation barrier, presents maintenance difficulties.
U.S. Pat. No. 4,377,352, issued Mar. 22, 1983 to Goodstein, describes a self-actuating water containment barrier for guarding open fields along flooding streams or rising lakes. The barrier comprises a plurality of stanchions which are mounted for pivotal movement from a normal dormant horizontal position, to an active vertical position. The stanchions are interconnected with water barrier-forming sheeting to form a barrier which can conform to a particular land mass or shoreline. Float members are mounted on the bottom of the outer ends of the stanchions. At low water levels, the float members rest on a shallow body of water or on the ground in a near horizontal position. As the level of the water rises, the float members cause the adjacent stanchions to pivot into a vertical position, thereby raising the sheeting between them to form a water barrier. This water barrier float system is unsuitable for guarding openings to constructions where cars or human beings must normally pass over the apparatus involved during the long times when the apparatus is retracted at rest.
This invention provides a flood guard method and apparatus for automatically refusing admission of rising surface water into a structural opening of a construction. By xe2x80x9cconstructionxe2x80x9d is meant any structure, building, erection, edifice or the like, and includes interior and exterior partitions and walls, in which openings such as doors or windows may occur, for passage from outside the construction to its interior, or within the construction from one room to another, or from one side of a partition to the other side, and this includes elongated passages such as tunnels and halls. The construction and the opening in the construction may be at ground level or below ground level, such as an underground parking garage, a basement, a subterranean tunnel or other subterranean space, so long as access to the construction or from one part of the construction to another is by an opening through which water can flow under the force of gravity. The essential factor is that the invention guards against flooding from surface water through an opening to the construction.
In general, the invention involves (i) pivoting a buoyant and structurally rigid flood gate from adjacent grade about an axis at the base of the gate arranged adjacent the bottom of a construction opening generally parallel to grade, such that, on rise of surface water sufficient to float the gate, the gate is buoyed and by force of rising water is rotated about the pivot axis in the direction of the opening, and (ii) as the gate buoyantly rotates upwardly, preventing the rising water from flowing around the sides of the gate sufficiently that enough hydraulic pressure is impressed on the gate by the rising water to push the gate into closing contact with stops or jambs adjacent the sides of the opening, thereby closing the opening and barring admission of flood water into the construction. The combination of an initial buoyant rotation of the gate upwardly about a horizontal axis followed by hydraulic force from water accumulated against the back of the up-rotated gate completes closure of the opening (with closure maintained by impress of hydraulic pressure). With a buoyant flood gate reposed at grade, the buoyant action of the gate in response to rising surface water is a rotational closing force for less than half the closing movement, when hydraulic pressure forces from water accumulating on the water side of the gate take over and complete the closing movement. Gate buoyancy, dependant on a variety of factors, including amount and kind of buoyant material, weight, and height verses width of the gate, affects the relative degree to which buoyancy closing forces surrender primacy to hydrostatic closing forces in a particular design.
Thus this invention provides a method for automatically refusing admission of rising surface water into a structural opening of a construction, the opening having opening-limiting margins, including a bottom, sides and usually a top. The method comprises (a) housing a buoyant gate of dimension occlusive to at least a lower portion of the opening adjacently in front of the opening, substantially parallel to grade, pivotingly arranged about a pivot axis parallel to the bottom of the opening and in a recess into which surface water can flow, (b) providing a portal for admitting surface water into the recess to cause the gate to pivotingly buoy upwardly from the recess in a rotation closing towards the opening, and (c) preventing rising surface water from flowing around sides of the upwardly buoyed gate, whereby rising surface water accumulates behind the gate and hydraulic pressure of the rising surface water exerts a continuing closing force rotating the gate toward, thence occlusively across, at least a lower portion of the opening.
Apparatus is provided in accordance with the invention to perform the function of the invention. A self actuating flood guard for refusing admission of rising surface water into a structural opening of a construction, the opening having opening-limiting margins, including a bottom, sides and usually a top, comprises (1) a buoyant gate having a base, sides, a front, a back and dimensions occlusive of at least a lower portion of the opening, the base being arranged for location adjacent the bottom of the opening, (2) pivotation members hinging the gate at the base about a pivot axis parallel to the bottom of the opening and allowing the gate to rest substantially parallel and adjacent grade proximately in front of the opening for pivotation upwardly toward and transversely to the opening, (3) a pair of upright walls reaching from grade and extending alongside the sides of the gate at rest, the walls having facing surfaces spaced apart sufficiently to allow the gate to pivot upwardly between them toward the opening with the sides of the gate close enough to the facing wall surfaces to permit hydrostatic pressure of surface water rising from the grade to develop against the back of the gate effective to impart a closing force on the gate after the gate buoyantly has pivoted from rest upwardly about the axis, and (4) jambs adjacent the sides of the opening for confronting and stopping rotation of the gate about the axis when the gate is rotated a predetermined extent under the closing force of the rising water hydrostatic pressure, thereby putting the gate in a closed position refusing admission of rising water into at least a lower portion of the opening. The predetermined extent suitably but not necessarily is an extent that places the jambs substantially upright but not in excess of 90 degrees relative to the grade.
The flood guard advantageously comprises a housing for the gate and pivotation members, the housing including a floor and sides for containing the gate above the floor such that with the gate resident in the housing the front of the gate substantially closes the gate housing. In many applications the gate is weight bearing, and when resident in the housing, it provides a passageway for traffic into the construction through the opening.
The gate housing further comprises a surface water portal into the housing giving access to the floor of the housing when the gate is resident in the housing, the housing and gate being configured to permit surface water entering through the portal to rise beneath the gate and pivotingly buoy the gate upwardly from the housing for rotation about the axis toward the opening. Optionally the portal is located in the housing at least adjacent the location in the housing remote from where the base of the gate is pivoted.
A drain is provided in the gate housing to remove waters flowing into the housing. Typically the removed water is emptied to a storm water collector tributary such as storm sewer, ditch, canal or other water collecting and removal system, including return to streets to discharge from the street to ditches or to storm sewers accessed by inlets along the sides of the streets. The purpose of the drain is to prevent the gate from floating up and out of its housing on the occasion of a heavy downpour which has not become a flooding situation. So long as the storm sewer or other water collector system is not full, water will not back up in the drain but will flow out and be removed by the water collector system. But in a condition where storm sewers are full and flowing at maximum rate, a limiting condition has been reached; street water no is longer accepted in the storm sewer, piles up, spreads and rises. This is the situation where the gate self-actuates, because the gate housing drain can no longer discharge its received water, and water entering the housing portal rises, elevating the gate. Thus the gate does not elevate during a mere heavy downpour but only when there is rising surface water in a flooding condition.
Seals affixed to the sides of the gate sealingly closing the gaps between the sides of the gate and the facing wall surfaces during rotation of the gate toward the opening of the construction. Suitably the seals are contact seals, preferably of a type that compress when brought into engagement with the walls during rotation toward the opening.
In one embodiment the jambs are affixed to the upright walls adjacent the opening and reach upwardly from adjacent grade. The jambs may reach an elevation proximate the height of the upright walls adjacent the opening, and may and preferably do include a resilient sealing surface arranged to cooperate with facing surfaces of the front of the gate in the closed position to seal against admission of water between the jamb and the gate.
The gate comprises buoyant material, for example, it may comprise a plurality of sealed tubes arranged side by side, or a honeycomb core structure sealingly arranged between two rigid panels. Alternatively the gate may have a bladder for a flotation material.
While the rotation of the gate about a pivot axis parallel to the bottom of the opening to be protected describes an arc, the rise of surface water is planar to horizontal, so more than a right angular shape of the upright walls between which the gate rotates upwardly is surplus structure, although structure may be provided above the hypotenuse to the right angle triangle for appearance or architecturally pleasing reasons. The walls are, of course, water impervious.
The jambs may be affixed to the construction on the sides of the opening. Alternatively the jambs may be freestanding from grade level or may project toward the opening from the upright walls, but the jambs are always spaced apart not more than the spacing of facing surfaces of the walls. Where the jambs are freestanding, the jambs are arranged with respect to the construction to act as a barrage to water between the jambs and the construction. Where the jambs are part of the walls, the walls are arranged relative to the construction to form a barrage to water between the walls and the construction. In an application of the invention, the upright walls extend from the construction and in cooperation with the jambs and the gate in the closed position provide a barrage to water between the walls and the construction.
The invention works either where the grade on which it is installed is horizontal or is angled relative to horizontal, either declined or inclined. Thus the construction may be a parking garage with underground parking accessed by a downwardly sloped ramp in which the flood guard may be installed.
The system of the invention is completely passive and automatic. There is no power or maintenance requirement and the gate normally rests out of the way so that once it is installed, most people passing or driving over it don""t even realize it is there. The method and apparatus of this invention have advantages over a vertical rising gate such as disclosed in U.S. Pat. No. 5,460,462, described above. For one thing, hydrostatic pressure of the rising water works to the advantage of the flood gate system of this invention, rather than against it. As mentioned, in the buoyant vertically rising barrier, any forces generated by dammed water to one side of the barrier serve to press the barrier against its tracks, increasing friction and making the barrier more resistant to floating upwards to full elevation. In the instant invention, the water pressure actually pushes the gate into fully elevated position. The gate will fully close when the water reaches between about one-third to about one-half, e.g., about 35-45%, of the overall height of a normally horizontally retracted gate.
Further, installation of the barrier is vastly simplified due to its horizontal packaging. The buoyant gate and its housing can be as little as only about four inches in height, whereas a buoyant vertically rising barrier must be the installed to a depth equal to the full height of the barrier plus some additions for structural support. Installation in roadways, and particularly in parking garages or tunnel systems, where other structures may lie closely beneath, is made possible by the present invention due to the minimized need to excavate material. Actually the design of this invention can be installed without any digging at all where necessary; it can be installed on top of the approach surface to the construction opening and would look like a flat speed bump lying on the surface of the pavement.
Also, maintenance of the flood gate of the instant invention is greatly eased due to its horizontal nature. In the case of a flood, mud, debris, and other detritus is carried in the water. When the flood recedes, much of this material will fall out of the water and remain behind. Cleaning the flood gate of the instant invention will require the washing of a broad, flat pan compared to cleaning a tall, thin slot in the ground.
These and other advantages of the instant invention will become more apparent to those in the art from the description of an embodiment which follows after an identification of the drawings used in connection with the description.